I recently learned that there are basically two different types of png images – indexed and truecolor. Most pngs you find on the internet are probably the truecolor type. The truecolor type uses an rgb format, so each pixel is represented by either 24 bits (8 bit channel depth * 3 channels), or 48 bits (16 bit channel depth). In contrast, indexed images map each pixel onto a 256 (or less) color palette. Wikipedia has a nice graph on this. […] (Read more)

Rob and Spencer with zebras Once again I found myself needing to use imagemagick to do something, and was overwhelmed by the many options. After much fiddling around, I found out some options that worked for me. In this case, I wanted to extract iptc captions from images, so that I could then insert the caption in a webpage with php. I use Picasa to edit photos and add captions. Picasa adds in the captions in the iptc information, which […] (Read more)

thanksgiving collage I upgraded to Picasa 3 a couple weeks ago. I didn’t upgrade right away, because it took awhile for the linux version to come out. I can happily say that Picasa 3 works great under linux from my experience. It was easy to install (they had an rpm available), and it runs very nicely. It seems like it even runs a bit faster than Picasa 2.6. But best of all, it has some really cool new features. One […] (Read more)

I have recently been trying to transition from Mac to Linux, with much success for the most part, but a few hiccups as well, as is to be expected. One of the important uses of the computer for me is photo editing and sharing, especially since we got our Canon Rebel XT last year, which takes absolutely beautiful pictures. I had developed a fairly nice workflow on my Mac for photo editing and sharing, consisting of: Import pictures from camera […] (Read more)